Tabecha Dame nanoni Oishii desu

In a world where demons prevail and humans are rare, the demon Oobami is renowned for his giant horns. But no one has ever seen them... In reality, they're the size of a pea! When his junior, Akaishi, picks up his supplement meant to grow his horns, Oobami thinks he's in trouble. But instead, Akaishi approaches him, saying, "They're not out yet, but giant horns are guaranteed. I can make them grow." Akaishi forcefully tries to feed him by sticking a finger in his mouth...!?

(Source: Libre, translated)